How much so? The Sounders have a shot at becoming the first team in the history of America's longest running soccer tournament to win four straight titles when they face Sporting Kansas City on Wednesday.
For the Sounders, success in the Open Cup still ranks below success in MLS play. But Seattle views the competition with high regard, and rightfully so considering its success. Last year, the Sounders became the first club in more than 40 years to win three straight titles in the oldest competition in American soccer.
Sounders fans would like to see more success in the MLS Cup playoffs, but the team has shown impressive skill in maneuvering through the one-and-done format of the Open Cup. Whether forced to play on the road or in the comfy confines of its own secondary home stadium, Seattle has been perfect in the tournament since 2009 with 16 straight wins heading into Wednesday's final.
"It's a testament to the players, but for sure the coaches getting guys ready, motivated and believing in winning these," Seattle general manager Adrian Hanuer said. "We've gotten to play a lot of those games at home, but we've won a lot of tough games on the road as well. It's something I'm really proud of as an organization."
When Seattle beat Chicago at home in last year's final, the Sounders became the first club since New York Greek-American, from 1967-69, to win three straight in the tournament.
And just getting to the final this season is already a remarkable feat on an international level for Seattle. While the U.S. Open Cup isn't the same as knockout club tournaments in Europe, it's still a rare accomplishment to win four straight.
Manchester United has never won the FA Cup even three straight times. The last English club to win three FA Cups in a row was Blackburn Rovers ... in 1884-86.
Lille made five straight Coupe de France finals from 1945-49, losing the first and last and winning the three in the middle.
Two Spanish clubs have won four straight Copa del Rey titles: Real Madrid from 1905-08 and Athletic Bilbao from 1930-33.
The closest, most recent example is the Coppa Italy. Between 2005 and 2008, Internazionale and Roma met for the cup title each year with the two Serie A clubs splitting the four final meetings.
"It's hard to even imagine with as big as the tournament is and as old that it is that we could even be given the opportunity to do that. We're very aware," Seattle defender Zach Scott said. "Even last year aware of making history and being the first team in a very long time to win three, and now the fact that after a hard, probably our hardest qualifying run to get to the finals, to find ourselves in a position to do something that nobody has done."
This year could be Seattle's most impressive run.
The Sounders knocked out San Jose in the quarterfinals on the road then beat Chivas USA in the semis back home. Now they face Kansas City, which is tied with Houston for the lead in the Eastern Conference of the MLS standings and is 9-3-2 in home matches this season in all competitions.
"It would be something that would be pretty special for the team. I think what we've done so far has been special, but it would be special; it would be different, unique," Seattle coach Sigi Schmid said. "To do it away from home makes it a little bit tougher, but certainly makes it probably even more special."